hydrochfonc acid To the solution add 5 ml of potassium iodate solunon, a cnmson colour is produced which deepens on further addition of potassium

hydrochfonc acid To the solution add 5 ml of potassium iodate solunon, a cnmson colour is produced which deepens on further addition of potassium or alkalinity Dissolve 0.1 g in 10 ml of freshly boiled and cooled water and add a few drops of bromothymol blue solution Not more than 0 05 rnl of 0 01 M hydrochlonc acid or 0 OtM sodium hydroxide is required to change the colour of the solution Clarity of solution A 5 0% w/v solution in water is clear, Appendix G 1 Arninoantipyrine: Wet about 0 2 g with a few drops of water in test-tube and add 3 ml of ethanol (95%], shake until dissolved and add successively with shaking, 2 drops of dilute ammonia solunon, 5 drops of potassium femcyanide solution, 2 drops of liquefied phenol and 5 ml of water The solution acquires a green colour gradually but not an orange or pink colour. Heavy metals Not more than 20 ppm, determined by Method Am a solution prepared m the following manner Ignite 1.Og until completely ashed Dissolve the residue in a mixture of 23 ml of water and 2 ml of dilute acetic acid. Appendix 3.12 Arsenic To 1 0 g in a long-necked, round-bottomed flask add 5 rnl of sulphuric acid and bnng to the boil gently and continue boiling on a low flame until the solution acquires a light brown colour Cool, add dropwise about 5 ml of hydrogen peroxide solution [100 vol) and heat gently until the solution just boils and continue the heating until the solu